International airline passengers on edge about making their connections when their flights into the United States are late may have reason to relax when they're headed to Chicago and New York, where federal authorities are using new procedures to help travelers bypass long, snarled customs lines.

The program, first introduced at Chicago's O'Hare International Airport and then at John F. Kennedy International Airport, is designed to be proactive.

As soon as an airline knows a plane is late — sometimes even before it takes off for the U.S. — staff scan passenger lists to see who has a connecting flight and when. They flag those passengers who look like they may be in danger of missing their connections. Once the plane lands, arrival-gate attendants hand them bright-orange cards that allow them into the short, fast-moving customs lines.

At a time when Homeland Security officials are facing criticism for introducing full-body scanners, enhanced pat-downs and other measures that have raised passenger anxiety, the new program enables authorities to argue that they're also taking steps to make the airport experience less stressful.

The program dubbed Express Connection is also saving airlines millions of dollars they otherwise would spend rebooking passengers who miss their connecting flights.

"It's a win-win situation for everybody," said Kathleen Guerrero, customer service manager at O'Hare for American Airlines.

The program could be introduced at other major U.S. airports with large numbers of international flights. Los Angeles International Airport and Seattle-Tacoma International Airport are among those that have expressed interest.

"You feel so vulnerable and violated when you miss a flight," said Brian Bell, a Chicago-based spokesman for the U.S. Customs and Border Protection agency. "We all get beaten up — us, the airlines — when people are missing flights."

JFK began developing Express Connection several months after O'Hare and is using it in just two terminals, said John Saleh, a New York-based spokesman for the Customs and Border Protection agency.

"This is still in our infancy with us," he said. "Eventually we want to include all airlines and all terminals — that's the goal."

Since the program was set up at O'Hare in June, around 16,500 incoming international travelers who might have missed a connecting flight did not, according to figures cited by Larry Di Giannantonio, an assistant port director at O'Hare for Customs and Border Protection.

That translates into big savings for airlines: On average they lose $150 whenever someone misses a flight, so the number of travelers who didn't miss flights at O'Hare amounted to a combined savings of around $2.5 million over the six months, he added.

There's no data yet on the number of passengers who have used the program at JFK to date or on how much it has saved airlines, Saleh said.

On a recent afternoon at the customs checkpoints in O'Hare's international terminal, more than 300 people were corralled in regular lines that snaked from the front to the back of the hall. The express lanes used by those on late-running flights had only a few travelers.

Those with Express Connection cards at O'Hare take an average of 23 minutes to get through customs, while someone in the regular lines normally needs closer to an hour, according to figures compiled by federal authorities at the airport.

The program is also free, unlike a service administered by Customs and Border Protection, called Global Entry. For a fee, it allows pre-approved, low-risk frequent travelers into the U.S. to get through customs fast by using an automated machine.

O'Hare officials say Express Connection has been comparatively easy and cheap to implement, requiring no new infrastructure or additional manpower. While passengers running late get into a faster line, that doesn't mean document or baggage checks are hurried up, said Di Giannantonio.

"Procedures don't change at all for the officer," Di Giannantonio said. "Enforcement is not jeopardized at all."

At least some analysts are giving the project as it's been applied at O'Hare a thumbs up.

"This helps avoid those extremely awkward moments were desperate passengers have to beg for special attention, which adds stress to the whole airport environment," said Joseph Schwieterman, a transportation expert at DePaul University.

While representatives from the Los Angeles and Seattle airports have inquired about Express Connection, Bell said, there's no timetable for when other airports might implement such a program.

For a host of reasons, O'Hare might benefit inordinately from it, said Schwieterman. There's a single international terminal, removed from the main domestic terminals, and international flights tend to arrive in bunches from around noon to early evening — so customs lines can back up fast.

At other major U.S. airports, like Miami International Airport, international flights are more spread out, avoiding the congestion that's common at O'Hare.

Also at O'Hare, incoming international flights and the domestic connections are usually on the same airline — either United or American — so the logistics of getting a late passenger aboard a domestic flight are more straightforward. At other international airports, passengers often fly in on one airline and fly out domestically with another company.

The program evolved differently at JFK from Chicago to account for differences in layout and the type of international flights, Saleh agreed. JFK has five terminals that handle international flights and caters to a wider variety of flights, not just from Europe, but South America, Africa and Asia, he said.

"Express Connection has to be adapted to the unique conditions of each airport," he said.

Schwieterman said he could think of few downsides of the program, though he wondered if travelers and their agents might start to count on the service and allow for shorter connections times for O'Hare.

"That's a potential moral hazard, I suppose," he said. "You may be encouraging bad behavior."

The benefits also don't extend to those using domestic terminals only, at least not directly. International passengers who miss a connection do sometimes bump passengers off a domestic flight, and that could happen less frequently.